More than three decades after a jury convicted Kevin Cooper of a brutal hatchet attack that killed members of a Chino Hills family and a young boy staying with them, Cooper and his advocates still are fighting the conviction.

In the latest request, the death row inmate is seeking clemency and further testing, such as Touch DNA testing, to be performed on evidence including the murder weapon, the hatchet sheath, a T-shirt and the prison button — items that were presented at trial and have undergone previous testing.

Kevin Cooper listens as a judge sentences him to the death penalty in 1985. Cooper was convicted of murdering the Ryen family and a neighbor and attempted murder of the Ryen son in Chino Hills in 1983. (Staff file photo by Walter Richard Weis, Inland Valley Daily Bulletin/SCNG)

Portrait of Doug and Peggy Ryen with their daughter Jessica, 10, and son Joshua, then 8-years-old. Joshua was the only survivor of the 1983 incident.
(File courtesy photo, Inland Valley Daily Bulletin/SCNG)

Mary Ann Hughes hugs a friend for supporting her after listening to Mike Farrell on a speech against the death penalty at Cal Poly in Pomona February 9, 2005. Kevin Cooper was convicted of murdering Mary Ann Hughes’ son, Christopher, in Chino Hills.(Staff file photo by Thomas R. Cordova, Inland Valley Daily Bulletin/SCNG)

Ten-year-old murder victim Jessica Ryen, seen here in a 1981 file photo, and her wounded 8-year-old brother, Joshua, seen here in a 1982 file photo, were victims of a 1983 stabbing attack in their Chino Hills, Calif., home. Prison escapee Kevin Cooper was convicted of capital murder in 1985 in the deaths of Jessica, her parents and an 11-year-old family friend. Cooper is scheduled to die by lethal injection at California’s San Quentin prison Tuesday, Feb. 10.
(AP Photo/Files)

Former M*A*S*H television star Mike Farrell delivers a speech against the death penalty at Cal Poly in Pomona February 9, 2005. Farrell was confronted by protesters during his speech.(Staff file photo by Thomas R. Cordova, Inland Valley Daily Bulletin/SCNG)

Patrick Lewis, 40, of San Bernardino, signs a petition in protest of the scheduled execution of condemned murderer Kevin Cooper on Monday, Feb. 9, 2004, outside the County Government Center in San Bernardino. Cooper, 46, whose bid for clemency was denied by Gov. Arnold Schwarzenegger, won a stay of execution on Monday, hours before he was to be executed.
(Staff file photo by Gabriel Luis Acosta, The Sun/SCNG)

F. Douglas Ryen and his wife, Peggy Ann, seen here in 1983 file photos, were murdered in 1983 in their Chino Hills, Calif., home, along with their 10-year-old daughter Jessica, and an 11-year-old family friend. Prison escapee Kevin Cooper, who was convicted for the murders in 1985, is slated for execution Feb. 10, 2004. (AP Photo/File)

Mary Ann Hughes appears to become irritated while listening to Mike Farrell during a speech against the death penalty at Cal Poly in Pomona February 9, 2005. Kevin Cooper was convicted of murdering Mary Ann Hughes’ son, Christopher, in Chino Hills.(Staff file photo by Thomas R. Cordova, Inland Valley Daily Bulletin/SCNG)

Evangelist J.B. Martin, of San Bernardino, speaks out in protest of the execution of Kevin Cooper, Monday, Feb. 9, 2004, outside the San Bernardino County Government Center. (Staff file photo by Gabriel Luis Acosta, The Sun/SCNG)

Prison escapee Kevin Cooper, center, escorted by law enforcement officers, is seen in this 1983 file photo shortly after his arrest in Santa Barbara, Calif. Cooper, who was convicted in 1985 for the murders of F. Douglas Ryen and his wife, Peggy Ann, along with their 10-year-old daughter, Jessica, and an 11-year-old family friend, is scheduled to die by lethal injection Tuesday, Feb. 10 at California’s San Quentin prison for the crimes. (AP/File)

Protesters march along St. Francis Drake Blvd. near San Quentin State Penitentiary. (Marcio Jose Sanchez / Associated Press)

Activist Todd Chretien, middle, organizes protesters as they prepare to march near San Quentin State Penitentiary. (Marcio Jose Sanchez / Associated Press)

Family members follow the casket of Christopher Hughes out of Our Lady of Assumption in Claremont, June of 1983. Hughes was a house guest who was killed along with Doug, Peggy and Jessica Ryen in their Chino Hills home earlier that year. (Staff file photo by Walter Richard Weis, Inland Valley Daily Bulletin/SCNG)

Protesters march near San Quentin State Penitentiary. The 9th U.S. Circuit Court of Appeals is considering whether DNA evidence linking Cooper to the slayings should be retested amid repeated claims that Cooper is innocent and was framed by law enforcement two decades ago.
(Marcio Jose Sanchez / Associated Press)

The Rev. Jesse Jackson, middle, addresses protesters at the California State Penitentiary at San Quentin in San Quentin, Calif. on Monday, Feb. 9, 2003. A stay of execution was issued for death row inmate Kevin Cooper who was scheduled for execution at midnight on Feb 10. (Ross Cameron / Associated Press)

Portrait of Christopher Hughes who was murdered along with the Ryen family in Chino Hills in 1983. The Ryen family son, Joshua, survived the attack. Kevin Cooper received the death penalty for the murders and is set to be executed Tuesday, Feb. 10, 2004. (File courtesy photo, Inland Valley Daily Bulletin/SCNG)

Actor Mike Farrell, right, addresses a group of protesters as Rev. Jesse Jackson, left, and other religious and community leaders listen Tuesday, Feb. 3, 2004, in front of the church that California Gov. Arnold Schwarzenegger attends. They held a news conference to protest the scheduled execution of Kevin Cooper, calling on Gov. Schwarzenegger to halt the execution.
(AP Photo/Ric Francis)

Shujaa Graham, middle, a former inmate on San Quentin State Penitaniary’s death row, argues his case against the death penalty during a rally by opponents of the death penalty in downtown San Francisco on Tuesday, Feb. 3, 2004. It was the latest effort by death penalty opponents to save convicted murderer Kevin Cooper, 46, who is scheduled to die by lethal injection Feb. 10. (AP file photo/Marcio Jose Sanchez)

This photo shows the house in which Kevin Cooper hid out before the murders and the Ryen family home, where the 1983 Chino Hills murders took place. (File courtesy photo, Inland Valley Daily Bulletin/SCNG)

Pastor Chris Ponnet, center background, along with 25 worshippers attend Mass at St. Camillus Catholic Chapel Monday, Feb. 9, 2004, in Los Angeles, for the murder victims that death row inmate Kevin Cooper is scheduled to be executed for having killed. Pastor Ponnet, who opposes the death penalty, always holds a Mass the day before a scheduled execution for the victims of the crime, and the day after for the family of the person executed. On the altar is a photograph of Christopher Hughes who, along with three others, died in the killing. (Ric Francis / Associated Press)

Former United Press International reporter Kristina Rebelo-Anderson speaks at a news conference, Thursday, Feb. 5, in Los Angeles, as Kevin Cooper’s attorney Greg Evans, left, looks on. Attorneys for Cooper released sworn statements from Rebelo-Anderson, who covered Coopers murder trial in 1984-85, that point to alleged planted evidence in the investigation of the murder of a Chino Hills, Calif., couple, their 10-year-old daughter and their daughter’s 11-year-old friend in 1983. (AP Photo/Nick Ut)

Mug photo of Kevin Cooper who is convicted of murdering a Chino Hills family and neighbor with a hatchet in 1983. (File courtesy photo, Inland Valley Daily Bulletin/SCNG)

This is an undated California Department of Corrections handout photo of Kevin Cooper. Cooper is California’s first condemned inmate to obtain post-conviction DNA testing and is slated for execution Tuesday, Feb. 10, 2004
(AP Photo/California Department of Corrections)

This is the Ryen family house in Chino Hills. Kevin Cooper is accused of murdering Doug and Peggy Ryen, Jessica Ryen and Christopher Hughes inside with a hatchet in 1983. (File courtesy photo, Inland Valley Daily Bulletin/SCNG)

This photo shows the the two Chino Hills houses involved in the 1983 murders for which Kevin is on Death Row. The murders occurred in the Ryen home. Cooper admitted to hiding out in the next door house. (File courtesy photo, Inland Valley Daily Bulletin/SCNG)

Family photo of Chino Hills family Doug, Peggy and Jessica Ryen and eight-year-old Joshua Ryen, (sitting on horse), who was the lone survivor of hatchet the attack. (File courtesy photo, Inland Valley Daily Bulletin/SCNG)

This photo shows a bloody shoe print found in a sheet in Doug and
Peggy Ryen’s bedroom. Prosecutors say the print matches the size and
type of shoes Kevin Cooper received at the California Institution for
Men state prison before he escaped. (File courtesy photo, Inland Valley Daily Bulletin/SCNG)

San Bernardino County Sheriff Floyd Tidwell examines blood stains found on the doorway leading into the master bedroom in the Ryen family house, 1983.
(File courtesy photo, Inland Valley Daily Bulletin/SCNG)

Investigators stand outside the master bedroom of the Ryen’s Chino Hills home June 6, 2003 as they gather evidence at the scene of the murders.
(Staff file photo by Walter Richard Weis, Inland Valley Daily Bulletin/SCNG)

The Chino Hills family home where Doug, Peggy and Jessica Ryen were attacked and murdered in 1983. Eight-year-old Joshua Ryen survived the attack, but a neighbor sleeping over at the Ryen house, Christopher Hughes, was also killed. Kevin Cooper, an escapee from California Institute for Men at Chino, was convicted and received the death penalty for the murders. He is scheduled for execution Tuesday, Feb. 10, 2004. (Staff file photo, Inland Valley Daily Bulletin/SCNG)

Kevin Cooper listens during his preliminary hearing in Ontario in November 1983 for the murders in Chino Hills in June of 1983. (Staff file photo by Walter Richard Weis, Inland Valley Daily Bulletin/SCNG)

San Bernardino County prosecutors announced their opposition to Cooper’s request in a statement released Monday and called on Gov. Jerry Brown to respect the decisions of the jury, the trial judge, California Supreme Court and other courts that have reviewed the case.

“The families of the victims and the surviving victim have waited patiently for thirty-five years for justice in this case,” District Attorney Michael Ramos said in the statement. “They have endured not only the loss of their loved ones but also the repeated and false claims from Cooper and his propaganda machine designed to undermine public confidence in the just verdict.”

Portrait of Doug and Peggy Ryen with their daughter Jessica, 10, and son Joshua, then 8-years-old. Joshua was the only survivor of the 1983 incident.<br />(File courtesy photo, Inland Valley Daily Bulletin/SCNG)

The bloody June 4, 1983 attack for which Cooper was convicted and sentenced took the lives of Doug and Peggy Ryen; their 10-year-old daughter Jessica; and neighbor Chris Hughes, 11, who was staying overnight at the Ryens’ home. The boy was a friend of the Ryens’ 8-year-old son Joshua, who suffered a slashed throat but survived the attack.

Mary Ann Hughes, the mother of Chris Hughes, said Monday that she appreciates that Ramos has advocated and been there for the victims and their families.

“Too much seems to be about the criminals, and we forget about the victims,” Hughes said. Cooper’s conviction has been completely upheld, she said, and the latest move for more investigation is coming from anti-death penalty advocates.

“Unless you’re a victim, you don’t know how important it is to have someone who is reaching out to help because it’s the right thing to do and they believe in the judicial system,” said Hughes.

Hughes also said this latest effort is happening because Brown is leaving office soon.

Cooper’s attorney, Norman Hile of Orrick Herrington and Sutcliffe LLP, said all they’re asking for is to allow advanced, state-of-the-art DNA testing to be completed — the type of testing not available when Cooper went to trial. Hile pointed to the recent identification of the Golden State Killer through advanced DNA testing.

“Why wouldn’t we want it done before executing someone who may be totally innocent?” Hile said.

Kevin Cooper listens during his preliminary hearing in Ontario in November 1983 for the murders in Chino Hills in June of 1983. (Staff file photo by Walter Richard Weis, Inland Valley Daily Bulletin/SCNG)

Cooper’s trial took place before the use of Touch DNA testing, which analyzes skin cells left behind on evidence, but prosecutors say it can’t provide relevant information in this case or exonerate Cooper, according to the statement.

The hatchet and protective sheath were touched by the owners of the hideout house — a place near the Ryen’s home where Cooper stayed upon first escaping from prison — their families, visitors and guests whenever the hatchet was used to chop firewood. Consequently, many people have touched the exhibits outside of laboratory conditions, prosecutors say.

Ramos said, in the statement, this is another attempt by Cooper to avoid punishment.

For decades, San Bernardino County prosecutors have been fighting Cooper’s case in the courts, Ramos said.

“Every judge has said this man is guilty. He is not innocent,” Ramos said.

The type of DNA testing that Cooper seeks is not going to help anyone, according to the district attorney. The hatchet was touched by many civilians. There’s unknown DNA on it.

“We call it a red herring,” he said.

Ramos said he believes Brown will do the right thing and deny Cooper’s request.

The case has been reviewed by the California Supreme Court, which determined the evidence showed Cooper’s guilt. Prosecutors say the hatchet, button and T-shirt were subjected to serological testing in 1983-84 and DNA testing in 2002.

In 2001, prosecutors agreed that Cooper should get post-conviction DNA testing. His own DNA expert participated in selecting the items to be tested.

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DNA testing was conducted in 2001 and 2002, and the results did not exonerate Cooper. The testing showed he was in the Ryens’ home at the time of the murders, that he smoked cigarettes in their station wagon after he stole it, and that his blood and the blood of at least one victim was on a T-shirt found by the side of a road leading away from the murders, according to prosecutors.

Cooper’s execution was stayed in 2004 when he argued that a simple scientific test and further examination of some of the evidence would show he is innocent. He received the additional scientific testing and expert examination of physical evidence collected in the case.

Despite Cooper’s claims that the tests and examination would show his innocence, a federal judge determined that Cooper alone was responsible for the deaths.

Hile, Cooper’s attorney, described Ramos’ statement about the DNA testing as inaccurate.

“It implies that there has been much DNA testing, and that’s not true,” Hile said. The only time there was DNA testing was in 2002, and for the testing done in 2004, we proved the results were falsified, he said.

Hile said they showed the DNA tests of the T-shirt that was found near the crime scene was planted by the San Bernardino County Sheriff’s Department, who investigated the killings.

“There hasn’t been DNA testing since then, and more importantly, there hasn’t been testing at any time with the technology available today,” Hile said.

With advanced DNA testing, Hile said they could find out who had worn the T-shirt — something that could not be shown in 2002. It would show that Kevin Cooper was not the culprit, he said.

“Why wouldn’t Mike Ramos want to get to the truth in this case?” asked Hile.